Concrete examples of unintentional adversarial AI behaviour
There is the case of the tesla accident where the car was in autopilot and crashed into a truck because it appears the vehicle mistook a lightly coloured truck for the sky, killing the driver: https://www.newscientist.com/article/2095740-tesla-driver-dies-in-first-fatal-autonomous-car-crash-in-us/

Having said that, it appears the car had been trying to tell the driver to pay attention: http://uk.reuters.com/article/us-tesla-crash-idUKKBN19A2XC